JP2022545674A - coil element - Google Patents

Abstract

a first core element (1) and a first winding body (2) having a winding axis (20) arranged around a winding support (11) of said first core element and the first winding body has a first foil conductor element (21), the first foil conductor elements are stacked one above the other along the stacking direction (S) and are electrically connected to each other. It has a plurality of conductor foils (22) insulated and arranged, the lamination direction is parallel to the winding axis, and the first winding body extends around the winding axis to form the second winding body. A coil element is presented comprising a plurality of windings of one foil conductor element in a helical fashion. [Selection drawing] Fig. 4B

Description

A coil element is presented.

For example, in power converter coils and chokes, AC losses are becoming an increasingly critical design factor due to rising clock frequencies. Due to AC winding losses, the optimization possibilities are limited at high power and at the same time high frequency. Hitherto, stranded or rectangular copper wires have been mostly used for such applications.

At least one challenge of certain embodiments is to present a coil element.

This problem is solved by subject matter according to the independent claims. Advantageous embodiments and development features of the subject matter are set out in the dependent claims and become apparent from the following description and the drawings.

According to at least one embodiment, the coil element has at least one core element and at least one winding body. In particular, the coil element can have at least one first core element and at least one first winding body.

According to a further embodiment, the first winding body has a first foil conductor element. The first foil conductor element has a plurality of conductor foils stacked one above the other. The first foil conductor element can in particular have at least 10, or preferably at least 20 or particularly preferably at least 50 conductor foils. For example, the first foil conductor element has 100 stacked conductor foils. The direction in which the conductor foils overlap each other can also be referred to as the lamination direction. The conductor foils of the first foil conductor element are therefore arranged one on top of the other along the stacking direction. Each of the conductor foils can be strip-shaped and can have a length, width and thickness. The length is particularly preferably greater than the width, which is particularly preferably greater than the thickness. The lamination direction is oriented perpendicular to the length and width and parallel to the thickness direction, so that the first foil conductor element has at least the entire thickness of the conductor foil. It has a height in the stacking direction that corresponds to the total. Particularly preferably, each of the conductor foils has or is formed from a metal band, which particularly preferably comprises or consists of copper.

According to a further embodiment, the first core element has a winding support. The first winding body is arranged around the winding support and has a winding axis. In other words, the first foil conductor element is wound around the winding support of the first core element, thereby defining the winding axis. The direction along the winding axis may also be referred to here and below as the vertical axis. The direction perpendicular to the winding axis can also be called the horizontal direction. The first winding body is in particular arranged helically with a plurality of windings of the first foil conductor element around the winding axis. In other words, the first winding body has a plurality of windings of the first foil conductor element helically around the winding axis. Each rotation of the first foil conductor element around the winding support can here form one winding.

According to a further embodiment, the lamination direction is parallel to the winding axis. In other words, the conductor foils are arranged one above the other along the direction of the winding axis and thus vertically. The direction defined by the thickness of the conductor foil is therefore parallel to the winding axis. The conductor foil extends spirally around the winding axis in a horizontal plane parallel to the length and width of the conductor foil. That is, the longitudinal direction of the foil conductor, and thus the longitudinal direction of the first foil conductor element, extends helically around the winding axis and thus around the winding support. Due to the described configuration and arrangement of the first foil conductor element, up to the corner of the winding chamber provided in the first core element for the first winding body, the first foil conductor element can be placed. The winding support is arranged in the center of the helically wound first foil conductor element and can also be referred to as the so-called core of the core element.

Particularly preferably, the winding support has a greater height in the vertical direction, ie in the direction parallel to the winding axis, than the first foil conductor element. Further, the winding support can adjoin the air gap in the vertical direction. By leaving free a region adjacent to the air gap, which may also be referred to as a central region in the mirror-symmetrical arrangement described below, having a second core element and a second winding body, Stray magnetic fields can be reduced or even avoided.

Furthermore, the conductor foils of the first foil conductor element are electrically insulated from each other. For this purpose, an electrically insulating material can be arranged between the conductor foils. Particularly preferably, the electrically insulating material has a smaller thickness than the conductor foil, for example a thickness 10 times or more smaller. The electrically insulating material can be formed, for example, by electrically insulating plastic foil strips arranged one above the other with conductor foils. Furthermore, conductor foils with electrically insulating plastic material can be partially or completely deformed in width and thickness. For this purpose, the conductor foil can be coated, for example, with an electrically insulating synthetic paint. The stacked conductor foils of the first foil conductor element are preferably connected in parallel with each other.

According to a further embodiment, magnetic material is arranged between the windings of the first winding body. Particularly preferably, magnetic material is arranged between immediately adjacent windings. Preferably, the magnetic material has a magnetic permeability less than or equal to that of the first core element. Particularly preferably, the magnetic material has a magnetic permeability of 10 or more and 100 or less.

For example, the magnetic material is formed by a magnetic band, also called magnetic tape, which is wound around the winding support together with the first foil conductor element. The magnetic band can, for example, comprise a plastic material forming a support material, in and/or on which ferritic and/or iron-based particles, powder particles and/or nanocrystallites are present. , are placed. Additionally, the first foil conductor element can be embedded in a magnetic material. By way of example, a magnetic paint formed by a plastics material containing e.g. ferritic and/or ferrous particles, powder particles and/or nanocrystallites can be used for this purpose. The first foil conductor element can have sides parallel to the lamination direction, in particular perpendicular to the width direction, on which the magnetic material is applied. Alternatively or additionally, the first core element may have a web-like portion forming the magnetic material and between the windings of the first foil conductor element. are placed. In other words, the first core element may have a channel extending spirally around the winding support, in which channel the first foil conductor element is preferably completely embedded. , are placed.

According to a further embodiment, the magnetic material has a height along the lamination direction and thus in the vertical direction equal to or greater than the height of the first foil conductor element. Particularly preferably, the magnetic material has a height in the vertical direction that is greater than the height of the first foil conductor elements in the vertical direction. In other words, the magnetic material is higher in the vertical direction than the first foil conductor elements and can therefore exceed the first foil conductor elements in the vertical direction.

According to a further embodiment, the first core element comprises a magnetic core material. For example, the first core element includes a ferritic magnetic material. Alternatively or additionally, the core element comprises a magnetic material based on one or more materials selected from Ni-Fe-Mo, Ni-Fe, Fe-Si-Al and Fe-Si, or It can consist of For example, the core element comprises or consists of Fe--Si--Al with a mixing ratio of Fe:Si:Al of 85:9:6. Such material, also known as Sendust, is a soft magnetic material with high permeability, low magnetic losses and good temperature stability. Additionally, the core element may comprise Fe--Si containing a 6.5% Si mixture. Such materials, also known under the name Mega Flux, are characterized, inter alia, by high magnetic flux densities and high temperature stability compared to other materials. The magnetic material for the first core element can be manufactured, for example, in powder form and sintered into the desired shape for the core element.

The first core element can have or be, for example, a pot core or an E core. Additionally, other or similar core geometries are possible, such as planar cores or ER cores. Furthermore, the coil element can have, for example, a further core element, which is formed, for example, as an I-core or disc-shaped and forms a magnetic circuit with the first core element. can be positioned over the first core element such that the

Particularly preferably, the coil element has a second core element and a second winding body in addition to the first core element and the first winding body. The embodiments and features described above for the first core element 1 and the first winding body apply equally to the second core element and the second winding body. Thus, the second winding body can in particular have a second foil conductor element, which has one or more of the features described for the first foil conductor element. have. Additionally, a magnetic material can be disposed between the turns of the second winding body, the magnetic material being one of the magnetic materials described in connection with the first core element and the first winding body. It can have the above characteristics. Particularly preferably, the first and second core elements can be of similar design. Furthermore, particularly preferably, the first and second winding bodies can be of similar design. The first and second winding bodies are preferably connected in series with each other.

A second core element with a second winding can be placed over the first core element with the first winding. In particular, the two core elements can be arranged one on top of the other such that the first and second winding bodies are arranged opposite each other. Particularly preferably, the second core element with the second winding body can be arranged on the first core element with the first winding body in mirror symmetry.

In the coil elements described here, according to a particularly preferred embodiment, in particular at least one foil conductor element is used in connection with the core element (i.e. combined with each other electrically insulated in the thickness direction). At least one laminate with a plurality of conductor foils stacked), the conductor foils can particularly preferably be connected in parallel with one another. The foil conductor element is wound around the winding support of the core element about a winding axis parallel to the lamination direction. Such conductor elements can be arranged in the core element up to the corners of the winding chamber in this configuration. The magnetic field guidance can be improved by the additional use of a magnetic material such as, for example, a magnetic tape wound around the winding support parallel to the foil conductor element, as described above. . As mentioned above, instead of magnetic tape, the foil conductor elements can be embedded in a magnetic material, or a separate magnetic material, which can be formed, for example, by the helical web of the core element, is used as a magnetic field guide. can be placed between the windings as Further particularly preferred features are, as mentioned above, leaving the central region free in the air gap to reduce or avoid stray magnetic fields in the air gap, and the core element shape, e.g. pot-core or E-core. can be the possibility of using

Particularly preferably, with coil elements according to at least some embodiments, it may be possible to reduce losses with moderate technical effort compared to conventional coil designs having substantially the same dimensions. In the case of the coil elements described here, it is particularly advantageous that the AC losses can be significantly reduced compared to conventional coil technology. Thereby, use at higher frequencies than with known coils can also be made possible.

Further advantages, advantageous embodiments and developments emerge from the exemplary embodiments described below in connection with the drawings.

1 is a schematic diagram of a coil element according to one embodiment; FIG. 1 is a schematic diagram of a coil element according to one embodiment; FIG. 1 is a schematic diagram of a coil element according to one embodiment; FIG. Fig. 10 is a schematic diagram of a coil element according to a further embodiment; Fig. 10 is a schematic diagram of a coil element according to a further embodiment; Fig. 10 is a schematic diagram of a coil element according to a further embodiment; Fig. 10 is a schematic diagram of a coil element according to a further embodiment; Fig. 10 is a schematic diagram of a coil element according to a further embodiment; Fig. 3 is a schematic view of part of a foil conductor element of a coil element according to a further embodiment; Fig. 10 is a schematic diagram of part of a coil element according to a further embodiment;

Identical, similar, or equivalently functioning elements in the embodiments and drawings may each be provided with the same reference numerals. The illustrated elements and their size ratios relative to one another are not to scale, but rather individual elements, such as layers, parts, members and regions, may be better illustrated and/or illustrated. It may be shown exaggeratedly for the sake of understanding.

1A-1C, a coil element 100 comprising a core element 1 and a winding body 2 is shown. In view of the examples below, the core element 1 and the winding body 2 will be referred to as the first core element 1 and the first winding body 2 . A schematic cross-sectional view of a coil element 100 is shown in FIG. 1A. The first winding body 2 has a first foil conductor element 21 . A schematic view of a portion of the first foil conductor element 21 is shown in FIG. 1B. FIG. 1C shows a schematic view of a portion of a first foil conductor element 21 according to an alternative embodiment. Unless otherwise stated, the following description applies equally to FIGS. 1A-1C.

The first foil conductor element 21 comprises a plurality of conductor foils 22 stacked one above the other, as can be seen in FIGS. 1B and 1C. The first foil conductor element 21 can have, in particular, at least 10, or preferably at least 20, or particularly preferably at least 50 conductor foils 22 . In a particularly preferred embodiment, the first foil conductor element 21 has for example 100 stacked conductor foils 22 . The direction in which the conductor foils are arranged on top of each other is called the stacking direction S and is shown in FIGS. 1A-1C, respectively.

Each of the conductor foils 22 of the first foil conductor elements 21 is formed in a strip shape, and has a width B perpendicular to the lamination direction S and a width B perpendicular to the lamination direction S, as shown in FIG. and parallel thickness D. Furthermore, each of the conductor foils 22 has a length along its longitudinal direction perpendicular to the width B and the thickness D, which respectively characterize the maximum extent of the conductor foil 22 . Therefore, the length is greater than the width B, which is greater than the thickness D. In the illustrated embodiment, each of the conductor foils 22 is formed by a copper strip. Alternatively, other metallic materials are possible.

The conductor foils 22 of the first foil conductor element 21 are arranged electrically insulated from one another. For this purpose, an electrically insulating material 23 is arranged between the conductor foils 22 , which particularly preferably has a thickness d smaller than the thickness D of the conductor foils 22 . For example, D/d≦10. The electrically insulating material 23 can be formed, for example, by electrically insulating plastic foil strips arranged alternately with the conductor foils 22 .

To produce the first foil conductor element 21, for example, copper foil and plastic foil can be alternately stacked one on top of the other, fixed or laminated, and if necessary cut to the desired shape. It is also possible, for example, to wind copper and plastic foils in a number of turns corresponding to the desired number of layers on a roller, fix them and cut them so that a flat laminate can be produced on removal from the roller. Furthermore, three-dimensional printing methods are also conceivable. As shown in FIG. 1C, the conductor foils 22 can also be individually coated with, for example, an electrically insulating synthetic paint as an electrically insulating material 23 and stacked one above the other.

The first foil conductor element 21 has a height H shown in FIG. 1A, said height H being at least the sum of the thicknesses D of all conductor foils 22 and in particular the conductor foils 22 and the electrical conductors therebetween. It corresponds to the sum of the thicknesses D and d of the insulating material 23 . For example, in the case of an electrically insulating paint as the electrically insulating material 23 , the thickness d of the electrically insulating material is even negligible compared to the thickness D of the conductor foil 22 . The width B of the first foil conductor element 21 substantially corresponds to the width B of the conductor foil 22 . As shown in FIGS. 1B and 1C, the first foil conductor element 21 is bounded in the width direction by side surfaces 24 which, depending on the method of manufacture, can be formed as shown in FIG. 1C. Additionally, it can be covered with an electrically insulating material 23 .

For example, 100 conductor foils 22 can be used for the first foil conductor element 21, which in the first foil conductor element 21 each have a thickness of 150 μm and a width in the range from 1 to 2 mm. , so that the first foil conductor element 21 can in this case have a height of, for example, about 15 mm and the aforementioned width. Alternatively, larger and smaller dimensions are possible depending on the application. In particular, the coil elements described can be characterized in that the dimensions of the individual components are easily scalable and are not limited to specific sizes.

The stacked conductor foils 22 of the first foil conductor element 21 are connected parallel to each other at the longitudinal beginning and end, but such wiring and electrical connections are shown for clarity. do not have.

The first core element 1 can have or be, for example, a pot core or an E core. Alternatively, other or similar core geometries are possible, such as planar cores or ER cores. Furthermore, the coil element 100 can have, for example, further core elements, which are formed, for example, as I-cores or disk-shaped and form a magnetic circuit together with the first core element 1. It can be arranged on the first core element 1 so as to be able to do so.

For example, the first core element 1 contains a ferritic magnetic material. Furthermore, other materials are also possible, for example based on one or more selected from Ni--Fe--Mo, Ni--Fe, Fe--Si--Al and Fe--Si. For example, the core element 1 comprises or consists of the materials Sendust or Mega Flux mentioned in the general section.

The first core element 1 has a winding support 11 . The first winding body 2 is arranged around the winding support 11 and has a winding axis 20 shown in FIG. 1A. The first foil conductor element 21 is spirally wound around the winding support 11 of the first core element 1 , thereby defining the winding axis 20 . The winding support 11 is therefore arranged in the center of the helically wound first foil conductor element 21 and can also be referred to as the so-called core of the core element 1 . The direction along the winding axis 20 can also be referred to as the vertical axis. The direction perpendicular to the winding axis 20 can also be called the horizontal direction. Thus, in a section corresponding to a horizontal section through the first winding body 2, the first winding body 2 spirals with a plurality of windings of the first foil conductor element 21, winding axis 20 It will be appreciated that the . Correspondingly, the first winding body 2 has a plurality of windings of the first foil conductor element 21 around the winding axis 20 . Each rotation of the first foil conductor element 21 around the winding support 11 here forms one winding. In the cross-sectional view of FIG. 1A, adjacent windings are shown spaced apart for clarity. Alternatively, the windings can be arranged directly adjacent to each other. This may be possible in particular if the side surfaces 24 of the first foil conductor element 21 are covered with an electrically insulating material. Alternatively, it is also possible to wind an electrically insulating foil together with the first foil conductor element 21 around the winding support 11 such that adjacent windings are electrically separated from each other by the electrically insulating foil. obtain.

As can be seen in FIG. 1A, the lamination direction S extends parallel to the winding axis 20. In FIG. In other words, the conductor foils 22 are arranged one above the other along the direction of the winding axis 20 and thus vertically. The direction set by the thickness D of the conductor foil 22 is therefore parallel to the winding axis 20 . The conductor foil 22 spirally extends around the winding axis 20 in a horizontal plane parallel to the length and width of the conductor foil 22 .

The first core element 1 further has an edge 12 which, together with the winding support 11, defines a winding chamber 13 in which the first winding body 2 is arranged. Depending on the design of the first core element 1, for example as a pot core or E-core, the edge 12 can completely or at least partially surround the first winding body 2 in the horizontal plane. Due to the described configuration and arrangement of the first foil conductor element 21 , up to the corner of the winding chamber 13 provided in the first core element 1 for the first winding body 2 , the first of foil conductor elements 21 can be arranged.

As further shown in FIG. 1A, the winding support 11 is positioned vertically, i.e. parallel to the winding axis 20, more than the first foil conductor element 21 and thus the first winding body. It can have a height greater than two. Furthermore, the winding support 11 can have a smaller height than the edge 12 in the vertical direction. Thus, a vertical air gap may be formed above the winding support 11 if the first core element 1 is covered by further core elements. By leaving the area of the winding support 11 adjacent to the air gap free, it may be possible to reduce or even avoid stray magnetic fields in the air gap, depending on the geometry.

FIG. 2 shows a further embodiment of a coil element 100 comprising, in addition to the first core element 1 and the first winding body 2, a second core element 1' and a second winding body 2'. ,It is shown. The features described above for the first core element 1 and the first winding body 2 apply equally to the second core element 1' and the second winding body 2'. Particularly preferably, the first and second core elements 1, 1' can be designed similarly, as shown. The second winding body 2 ′ thus has a second foil conductor element 21 ′ designed similarly to the first foil conductor element 21 . The first and second winding bodies 2, 2' and thus the first and second foil conductor elements 21, 21' are preferably connected in series with each other.

A second core element 1' with a second winding body 2' is arranged on top of the first core element 1 with the first winding body 2, the first and second winding bodies 2, 2 ' are positioned opposite each other. As can be easily recognized, the second core element 1' with the second winding 2' is stacked in the stacking direction S on the first core element 1 with the first winding 2'. The edges 12, 12' of the first and second core elements 1, 1' can bear against each other.

Between the winding supports 11, 11' of the first and second core elements 1, 1', the height of the winding supports 11, 11' is small compared to the respective edge 12, 12'. Due to this, a void 4 is formed. Due to the fact that the winding bodies 2, 2' also have a smaller height than the winding supports 11, 11', each winding support 11, 1' has an area that remains free. By leaving free the regions of the winding supports 11, 11', respectively adjacent to the air gap 4, which may also be referred to as the central region, as explained in connection with the previous embodiment, Stray magnetic fields can be reduced or even avoided.

FIGS. 3A and 3B and FIGS. 4A and 4B, in cross-sectional and three-dimensional views (cut open in FIG. 4B for better understanding), respectively, relate to FIGS. 1A-1C and 2. A further embodiment of coil element 100 is shown, which is a variation of the embodiment shown. By way of illustration only, the core elements of Figures 3A-4B are formed as pot cores. Alternatively, other core shapes are possible, as discussed above.

Compared to the previous embodiment, in the embodiments shown in FIGS. 3A and 3B and FIGS. 4A and 4B, the windings of the first winding body 2 or the first and second winding bodies 2, 2' A magnetic material 3 is arranged between each. Particularly preferably, the magnetic material 3 is arranged between immediately adjacent windings, as shown. Preferably, the magnetic material 3 has a magnetic permeability less than or equal to that of the first core element 1 or the first and second core elements 1, 1'. Particularly preferably, the magnetic material 3 has a magnetic permeability of 10 or more and 100 or less.

3A-4B, the magnetic material 3 is each formed by a magnetic band 31, which can also be called a magnetic tape, which together with the respective foil conductor element 21, 21', the respective It is wrapped around the winding supports 11, 11'. The magnetic band 31 can, for example, comprise a plastic material forming a plastic support, in and/or on which are ferritic and/or iron-based particles, powder particles and/or nano-particles. Crystals are embedded or arranged.

The magnetic material 3 has a height in the vertical direction, i.e. along the stacking direction S, equal to or greater than the height of the respective foil conductor element 21, 21'. Particularly preferably, the magnetic material 3 has a height in the vertical direction that is greater than the vertical height of the respective foil conductor element 21, 21', so that the magnetic material 3 has a height in the vertical direction of the respective It is higher than the foil conductor elements 21, 21' and thus exceeds the foil conductor elements 21, 21' in the vertical direction.

By using magnetic material 3 parallel to the windings of the respective foil conductor element 21, 21' the magnetic field induction can be improved. Simulations have shown that, for example, the coil element 100 shown in FIG. 4 has corresponding core elements and dimensions in which a conventional stranded wire-based winding body is used that does not allow the use of magnetic material between windings. It can be shown to have significantly smaller AC winding losses compared to conventional coil designs.

As shown in Figures 3B and 4B, the parts of the foil conductor elements 21, 21' guided out through the openings of the respective core elements 1, 1' can form electrical connections. Alternatively, other electrical connections may be provided.

Instead of a magnetic band as the magnetic material 3, the first foil conductor element 21 or the first and second foil conductor elements 21, 21' can be embedded in the magnetic material 3, respectively. plastic containing e.g. A magnetic paint 32 formed by the material can be used for this purpose. To this end, the magnetic material 3 can preferably be applied onto the side surfaces 24 before being wound onto the winding supports of the core element.

As shown in part of the first core element 1 with the first winding body 2 in FIG. 6, the first core element 1 according to a further embodiment forms the magnetic material 3 and the It is also possible to have web-like portions 14 arranged between the windings of one foil conductor element 21 . In other words, the first core element 1 can have a channel extending spirally around the winding support 11, in which channel the first foil conductor element 21 is preferably completely placed buried. In the case of a coil element 100 having a second core element 1', as shown in Figures 4A and 4B, the second core element 1' has a corresponding web-like portion and thus a corresponding spiral channel. with a second foil conductor element disposed within the channel.

Features and embodiments described in connection with the drawings can be combined with each other according to further embodiments, even if not all combinations are explicitly described. Furthermore, the embodiments described in connection with the drawings may alternatively or additionally have further features according to the general part description.

The invention is not limited thereto by the description with reference to the examples. Rather, the invention covers all novel features and combinations of features, including in particular all combinations of features in the claims, even if such features or combinations themselves are expressly defined in the claims or examples. including even if not presented in

1, 1' core element 2, 2' winding body 3 magnetic material 4 air gap 11, 11' winding support 12, 12' edge 13 winding chamber 14 web-like portion 20 winding shaft 21, 21' foil conductor Element 22 Conductor foil 23 Electrical insulation material 24 Side 31 Magnetic band 32 Magnetic paint 100 Coil element B Width d Thickness D Thickness H Height S Lamination direction

Claims (16)

A coil element (100),
a first core element (1);
a first winding body (2) having a winding axis (20) arranged around the winding support (11) of said first core element;
has
The first winding body has a first foil conductor element (21), the first foil conductor elements are stacked one above the other along the stacking direction (S) and are electrically insulated from each other. having a plurality of conductor foils (22) arranged,
The stacking direction is parallel to the winding axis,
A coil element (100), wherein said first winding body comprises a plurality of windings of said first foil conductor element helically around said winding axis. 2. The method of claim 1, wherein an electrically insulating material (23) is arranged between the conductor foils in the stacking direction, said electrically insulating material having a smaller thickness along the stacking direction than the conductor foils. coil element. 3. The coil element according to claim 1, wherein each of said conductor foils is formed by a metal band. The coil element according to any one of claims 1 to 3, wherein the stacked conductor foils of the first foil conductor elements are connected in parallel with each other. A coil element according to any one of claims 1 to 4, wherein a magnetic material (3) is arranged between turns of said first winding body. 6. The coil element according to claim 5, wherein said magnetic material has a magnetic permeability less than or equal to that of said first core element. 7. The coil element according to claim 5, wherein said magnetic material has a magnetic permeability of 10 or more and 100 or less. 8. The coil element according to claim 5, wherein said magnetic material has a height along said lamination direction greater than a height of said first foil conductor element along said lamination direction. . Coil according to any one of claims 5 to 8, wherein the magnetic material is formed by a magnetic band (31) wound around the winding support together with the first foil conductor element. element. A coil element according to any one of claims 5 to 8, wherein said first foil conductor element is embedded in said magnetic material. 4. The first foil conductor element of claim 1, wherein said first foil conductor element has a side surface (24) parallel to said lamination direction, said magnetic material being applied onto said side surface of said first foil conductor element. 11. The coil element according to 10. The first core element has a web-like portion (14) forming the magnetic material and disposed between the windings of the first foil conductor element. The coil element according to any one of claims 5 to 8, comprising: The coil element according to any one of claims 1 to 12, wherein said first core element has a pot core or an E core. 14. The method of any of claims 1 to 13, comprising a second core element (1') and a second winding body (2'), said first and second winding bodies being connected in series with each other. The coil element according to any one of items 1 and 2. 15. The claim of claim 14, wherein the second core element with the second winding body is arranged in mirror symmetry above the first core element with the first winding body. coil element. 16. A coil element according to claim 14 or 15, wherein the first and second core elements are similarly designed and the first and second winding bodies are similarly designed.

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